Portal vein pneumatosis is an imaging sign of abnormal accumulation of gas in the portal vein and its intrahepatic portal vein branches due to a variety of causes, and is usually diagnosed by abdominal radiographs. It is commonly seen in neonatal necrotizing small bowel colitis. Neonatal necrotizing small bowel colitis is a serious disease characterized by abdominal distension, vomiting and blood in the stool, and cystic pneumatosis of the intestinal wall as an X-ray feature. Then, how to prevent and treat portal venous effusion? The following are the preventive treatments for portal vein pneumatosis: 1. Fasting Fasting for 3 days for suspected children, 7-10 days for confirmed cases. Severe cases 14 days or longer. When the clinical situation improves, abdominal distension disappears and fecal occult blood turns negative, the diet can be gradually resumed. Resumption of feeding should start with water, then feed sugar water, dilute milk, and gradually increase the concentration of diluted milk according to the condition. Gastrointestinal decompression should be carried out during the period of fasting. 3.Anti-infection ①Antibiotic selection: according to the bacterial culture and drug sensitivity test, when the bacteria are unknown, we can use benzylpenicillin, oxpiperazine penicillin or the third-generation cephalosporin, such as anaerobic bacteria preferred metronidazole. ② Course of treatment: 3 days for suspected children, 7-10 days for confirmed cases, 14 days or longer for severe cases. 4.Supportive therapy and other treatments During fasting, intravenous nutrition should be given to maintain energy and water-electrolyte balance, supplying 209kJ (50kcal/kg) per day, gradually increasing to 418-503KJ (100-120kcal/kg), and the amount of fluid should be 120-150ml/hg, with coagulation, and the amount of fluid should be 120-150ml/hg. 150ml/hg, fresh frozen plasma can be transfused if there is coagulation mechanism disorder, and antishock treatment can be given when shock occurs. Surgical treatment Surgery can be considered in case of obvious peritonitis, and immediate surgery should be performed in case of intestinal perforation.